ROS Node: Serial_Node

Author: Kevin Walchko

License: BSD

Language: C++

Website: http://github.com/walchko

Simple node that connects to a serial port and launches a ROS service. Ideally I would use rosserial, but that doesn't seem to work reliably and there appear (at this time) not to be any real progress done on it in the last several months.

This node looks for a simple message format:

< message size data >

where

• < is the start of a message
• message is one char (e.g., m, a, c, etc) that defines the type of message
• size is one byte that describes how much data follows, can be 0-255
• data is the message data

• is the end of a message

At this time I do not do any kind of check sum, but I am thinking about it.

Take a look in src/example.cpp for how to program to use this.

Command Line

rosrun serial_port serial_port <uC> <port> <baud> <debug>

• uC: a number that gets appended to the service topic incase there are multiple nodes running at once … 0, 1, 2, 3, …
• port: the serial port
• baud: the baud rate to connect at: 9600, …, 57600, 115200
• debug: enable debugging info printing ... just put true if you want it

Published Services:

The service message format is:

• request str: command sent to robot
• request size: size of returned message from robot, tells serial_node how much data to look for
• request time: how long (in msec) to wait for a response before declaring failure
• response str: the data sent back from the robot

The service is advertized as uc_serial where is the number you passed on the command line

Example:

rosrun serial_port serial_port 0 /dev/cu.usbserial 9600 true

To Do

• simplify using this